Search Publications
Comparative pick-up ion distributions at Mars and Venus: Consequences for atmospheric deposition and escape
Luhmann, Janet; Curry, Shannon M.; Hara, Takuya +3 more
Without the shielding of a substantial intrinsic dipole magnetic field, the atmospheres of Mars and Venus are particularly susceptible to similar atmospheric ion energization and scavenging processes. However, each planet has different attributes and external conditions controlling its high altitude planetary ion spatial and energy distributions. …
Organic chemistry in Titan's upper atmosphere and its astrobiological consequences: I. Views towards Cassini plasma spectrometer (CAPS) and ion neutral mass spectrometer (INMS) experiments in space
Sittler, E. C.; Ali, A.; Chornay, D. +2 more
The discovery of carbocations and carbanions by Ion Neutral Mass Spectrometer (INMS) and the Cassini Plasma Spectrometer (CAPS) instruments onboard the Cassini spacecraft in Titan's upper atmosphere is truly amazing for astrochemists and astrobiologists. In this paper we identify the reaction mechanisms for the growth of the complex macromolecules…
Submillimeter mapping of mesospheric minor species on Venus with ALMA
Lellouch, E.; Encrenaz, T.; Moreno, R. +2 more
Millimeter and submillimeter heterodyne spectroscopy offers the possibility of probing the mesosphere of Venus and monitoring minor species and winds. ALMA presents a unique opportunity to map mesospheric species of Venus. During Cycle 0, we have observed Venus on November 14 and 15, 2011, using the compact configuration of ALMA. The diameter of V…
Explosive volcanic activity on Venus: The roles of volatile contribution, degassing, and external environment
Wilson, C. F.; Glaze, L. S.; Airey, M. W. +3 more
We investigate the conditions that will promote explosive volcanic activity on Venus. Conduit processes were simulated using a steady-state, isothermal, homogeneous flow model in tandem with a degassing model. The response of exit pressure, exit velocity, and degree of volatile exsolution was explored over a range of volatile concentrations (H
Photochemical control of the distribution of Venusian water
Gao, Peter; Parkinson, Christopher D.; Esposito, Larry +3 more
We use the JPL/Caltech 1-D photochemical model to solve continuity diffusion equation for atmospheric constituent abundances and total number density as a function of radial distance from the planet Venus. Photochemistry of the Venus atmosphere from 58 to 112 km is modeled using an updated and expanded chemical scheme (Zhang et al., 2010, 2012), g…
COSIMA calibration for the detection and characterization of the cometary solid organic matter
Briois, Christelle; Cottin, Hervé; Fray, Nicolas +4 more
On the orbiter of the Rosetta spacecraft, the Cometary Secondary Ion Mass Analyser (COSIMA) will provide new in situ insights about the chemical composition of cometary grains all along 67P/Churyumov-Gerasimenko (67P/CG) journey until the end of December 2015 nominally. The aim of this paper is to present the pre-calibration which has already been…
The shape of the Venusian bow shock at solar minimum and maximum: Revisit based on VEX observations
Zhang, Tielong; Wang, Shui; Huang, Can +5 more
Several factors control the bow shock position at Venus, including short-term period responses (solar wind dynamic pressure) and long-term period variations (solar activity). Based on Venus Express (VEX) observations, we revisit the influence of solar activity on the Venusian bow shock location, by accurately determining not only the shock termina…
Asteroid lightcurve inversion with Lommel-Seeliger ellipsoids
Muinonen, Karri; Wilkman, Olli; Cellino, Alberto +2 more
We derive initial rotation, shape, and scattering properties for asteroids from sparse and dense photometry based on the so-called Lommel-Seeliger ellipsoid (LS ellipsoid). Due to the analytical disk-integrated brightness, the LS ellipsoid allows for fast rotation-period, pole-orientation, and shape analyses, as well as efficient Markov-chain Mont…
The SCITEAS experiment: Optical characterizations of sublimating icy planetary analogues
Thomas, N.; El-Maarry, M. R.; Pommerol, A. +3 more
We have designed and built a laboratory facility to investigate the spectro-photometric and morphologic properties of different types of ice-bearing planetary surface analogs and follow their evolution upon exposure to a low pressure and low temperature environment. The results obtained with this experiment are used to verify and improve our inter…
Venus mesospheric sulfur dioxide measurement retrieved from SOIR on board Venus Express
Vandaele, A. C.; Robert, S.; Wilquet, V. +5 more
SOIR on board Venus Express sounds the Venus upper atmosphere using the solar occultation technique. It detects the signature from many Venus atmosphere species, including those of SO2 and CO2. SO2 has a weak absorption structure at 4 µm, from which number density profiles are regularly inferred. SO2